A. Field of the Invention
The device of the present invention generally relates to bedding apparatus and, more particularly, to a new and improved mattress base or support member and frame assembly therefor that alternately forms a box or inner spring or a foundation.
B. Description of the Prior Art
A typical prior art bed assembly includes a mattress disposed above and supported by a box or inner spring, both of which are disposed above and supported by a lowermost adjustable frame. The adjustable frame typically includes four vertical support means, such as legs, rollers or casters, and maintains the bed assembly at a predetermined distance above the floor. An acceptable substitute for the box spring in supporting a mattress is a foundation that is formed by a solid resilient cushion, such as a sheet of polyurethane foam, disposed on a suitable frame.
Since it is desirable that a mattress be disposed above the floor at a generally uniform height, it is important that the box spring and the foundation have substantially the same thicknesses. A typical spring assembly for use in a box spring that provides the desired combination of resiliency and firmness is approximately 6 inches thick. Since it is desirable that the foundation used as a substitute for the box spring have the same thickness as the box spring, a 6 inches thick resilient cushion, such as a sheet of polyurethane foam, could be used in place of a spring assembly. However, a 6 inches thick sheet of polyurethane foam is relatively quite expensive.
It has been found that a 3 inches thick sheet of polyurethane foam provides the desired combination of resiliency and firmness at a substantially lower cost than the cost of a 6 inches thick sheet of polyurethane foam. Thus, the typical practice in the prior art has been to use a thicker foundation frame assembly to support the solid resilient cushion than the box spring frame assembly used to support the spring assembly. For this reason, inventories of the two frame assemblies are required to be kept, resulting in an increase in costs and bookkeeping efforts.
The prior art includes several disclosures of mattress bases that include mattress base frame assemblies capable of directly receiving vertical support means, such as legs, rollers or casters, thereby eliminating the need for an adjustable lowermost frame. For example, such mattress bases are disclosed in U.S. Pat. Nos. 2,908,918 and 3,076,979. The mattress bases disclosed in these prior art patents further function to support mattresses of different thicknesses above the mattress bases at the same height above the floor. That is, when disposed in the first condition, each of the frame assemblies of the mattress bases receive and support a mattress of a first thickness. When disposed in a second, inverted condition, each of the frame assemblies of the mattress bases receive and support a mattress of a different thickness at the same height above the floor. However, the prior art has not addressed or solved the problem of providing a single mattress base frame assembly that can be used to alternately support a spring assembly or support a resilient cushion to thereby eliminate the requirement for maintaining stocks of at least two different frame assemblies.